The River Valley
Rivers have a upper course (closest to the source of the river), a middle course and a lower course (closest to the mouth of the river).
As a river flows downhill, the gradient changes and it forms channels and valleys.
The Long profile of the river shows you how the gradient of the river changes over the courses.
The Cross profile shows you what the cross-section of the river looks like.
A river Erodes, transports and deposits. The shape of the valley and channel changes along the river depending on whether erosion or deposition is the dominant process.
Valley and channel shape: V Shaped valley with steep sides. A shallow channel.
Valley and channel shape: Gently sloping valley sides wider. Channel deeper.
Valley and Channel shape: Very wide, almost flat valley. Very wide deep channel.
There are two types of erosion to learn:
Vertical erosion: This deepens the valley and channel, making it 'v' shaped. It is dominant in the upper course.
Lateral erosion: This widens the valley and the channel. This is dominant in the middle and lower courses.